What is Propylene Glycol (PG) ?

July 3, 2017

Propylene Glycol is in cosmetics, processed foods, shampoos, lotions, perfumes, deodorants, over the counter drugs, and much more. You may have seen Propylene Glycol listed as 1,2-propanediol, PG, methyl glycol, trimethyl glycol.

Propylene Glycol is NOT ethylene glycol. I’ll get into lethal ethylene glycol next week.

According to the FDA Code of Federal Regulations, Propylene Glycol (1,2,-propanediol) is described to not occur in nature and is made by “treating propylene with chlorinated water to form the chlorohydrin which is converted to the glycol by treatment with sodium carbonate solution. It is also prepared by heating glyercol with sodium hydroxide.”

The FDA recognizes Propylene Glycol as “Generally Recognized As Safe” (GRAS) when used as a food additive.

Propylene Glycol uses include:

Anti-caking agent

Antioxidant

Dough strengthener

Emulsifier

Flavor agent

Formulation aid

Humectant (moisture preserver)

Processing aid

Solvent and vehicle

Stabilizer and thickener

Surfactant

Texturizer

Fun fact: The FDA prohibits the use of Propylene Glycol in cat food. (FDA)

The World Health Organization (WHO) describes propylene glycol as “…relatively safe in normal use, but cases of poisoning associated with its use as a vehicle for drugs or vitamins given intravenously or orally have been described.”

Propylene glycol breaks down in the body in about 48 hours. However, studies of people and animals show that if you have repeated eye, skin, nasal, or oral exposures to propylene glycol for a short time, you may develop some irritation. (ATSDR)

What about Propylene Glycol Esters in Cosmetics?

The Cosmetics Ingredient Review (CIR) Expert Panel concluded…

“…the following ingredients are safe in the present practices of use and concentration described in this safety assessment in cosmetics:

The Bottom Line…

Government regulations recognize Propylene Glycol to be generally safe in pharmaceuticals and foods. It is considered to be toxic in large doses. Toxic effects include hyperosmolality, increased anion gap metabolic acidosis (due to lactic acidosis), acute kidney injury, and sepsis-like syndrome. Due to it’s unnatural origin, I think I’ll pass on Propylene Glycol when possible.

Have questions about other questionable ingredients? Browse my Ingredients Defined page for answers.